This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.

The pthread_mutexattr_getpshared() function shall obtain the value of
the process-shared attribute from the attributes object referenced by
attr.
The pthread_mutexattr_setpshared() function shall set the process-shared attribute in an initialized attributes object referenced by
attr.
The process-shared attribute is set to PTHREAD_PROCESS_SHARED to
permit a mutex to be operated upon by any thread that has access to
the memory where the mutex is allocated, even if the mutex is
allocated in memory that is shared by multiple processes. If the
process-shared attribute is PTHREAD_PROCESS_PRIVATE, the mutex shall
only be operated upon by threads created within the same process as
the thread that initialized the mutex; if threads of differing
processes attempt to operate on such a mutex, the behavior is
undefined. The default value of the attribute shall be
PTHREAD_PROCESS_PRIVATE.
The behavior is undefined if the value specified by the attr argument
to pthread_mutexattr_getpshared() or pthread_mutexattr_setpshared()
does not refer to an initialized mutex attributes object.

Upon successful completion, pthread_mutexattr_setpshared() shall
return zero; otherwise, an error number shall be returned to indicate
the error.
Upon successful completion, pthread_mutexattr_getpshared() shall
return zero and store the value of the process-shared attribute of
attr into the object referenced by the pshared parameter. Otherwise,
an error number shall be returned to indicate the error.

The pthread_mutexattr_setpshared() function may fail if:
EINVAL The new value specified for the attribute is outside the range
of legal values for that attribute.
These functions shall not return an error code of [EINTR].
The following sections are informative.

If an implementation detects that the value specified by the attr
argument to pthread_mutexattr_getpshared() or
pthread_mutexattr_setpshared() does not refer to an initialized mutex
attributes object, it is recommended that the function should fail
and report an [EINVAL] error.

Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 PTHREAD_MUTEXATTR_GETPSHARED(3P)